Whirlpool M-17 Technical Manual page 62

COMPONENT TESTING (Cont.)
DANGER
Electrical Shock Hazard
Only authorized technicians should perform
diagnostic voltage measurements.
After performing voltage measurements,
disconnect power before servicing.
Failure to follow these instructions can result in
death or electrical shock.
ACU Diagnostic LED
The control is equipped with a single LED which is intended to
help diagnose if the ACU needs to be replaced. The LED has
different display patterns which indicate different states.
LED Slow Blinking: Normal ACU operation. Unrecoverable ACU
fault has been recorded. Power supply and microcontroller are
functional.
LED Solid ON: Power is applied to ACU, but no Setting File has
been programmed. Control is not functional in this state. Flash
Setting File (if service tool is available) or replace ACU.
LED Double Blink: Communication failure between ACU and HMI.
LED Fast Blink: ACU is performing initialization or ACU setting file
is in progress of being programmed. This should be a temporary
state that occurs briefly at power up.
LED OFF: An unrecoverable ACU fault has been recorded or no
power is applied to ACU. Check for 120 VAC across P4-1 and P4-4.
See "Service Fault Codes" table above.
LED Triple Blink: Incompatibility between ACU Setting File and
firmware.
3-24 Whirlpool and KitchenAid
n
®
For Service Technician Use Only
Filtration and Maytag
®
User Interface (UI)
This test will check the wiring to the user interface and the user
interface itself. The following items are part of the user interface
circuit:
n Harness/Connection
n User Interface (UI)
n Status LED (On some models)
n Control Board
Test Procedure
1. Verify that the control lock-out feature has not been turned
on by the customer. If unit will not run or power up, perform
Power Check procedure on page 3-8. Also, check for excessive
condensation on UI parts due to vent and/or fan problem.
2. Unplug dishwasher or disconnect power.
3. Remove toe and outer door panels to access control board.
4. Disconnect user interface connection from control board.
Verify all other connections to the control are good.
5. Plug in dishwasher or reconnect power.
6. Perform DC power supply voltage checks as described above
in "General Theory of Operation" section.
7. Repair/replace faulty parts.
8. Unplug dishwasher or disconnect power.
9. Reassemble all parts and panels.
10. Plug in dishwasher or reconnect power.
24" Microfiltration Dishwashers
®